The present invention relates to a process for the preparation of binary indole alkaloids, such as vinblastine or leurosidine, which are effective as an anti-cancer drug.
Conventional processes for the preparations, e.g. through chemical transformation of 3', 4'-anhydrovinblastine (AVLB), of binary indole alkaloids possessing an anti-tumor activity, such as vinblastine (VLB) and leurosidine (LEU) include e.g. the process disclosed in J. C. S. Chem. Commn. 583, 1979. However, the yields of object vinblastine (VLB) and leurosidine (LBU), etc., are very poor as low as 1 to 2%. Also, the processes employing an enzyme are disclosed in J. C. S. Chem. Commn. 257, 1979 and Phytochemistry 26(12), 3233 (1987). In these processes, however, there are disadvantages, such as very low yields, long reaction times, etc. Thus, both processes had problems for industrial production and were not satisfactory processes.